For about forty years, a popular hobby craft activity for both children and adults has been the production of three-dimensional objects from a heat-shrinkable sheet material known by the trademark SHRINKY DINKS, a registered trademark of K & B Innovations, Inc. The material consists of a sheet of thin plastic material that can be colored and/or cut out, and then heated to cause it to shrink and form thickened and hardened art forms. Typically the plastic sheet material is composed of a heat-shrinkable polystyrene base material coated with a water-insoluble, ink-receptive coating. The sheet material and some of its uses are described in U.S. Pat. No. 4,102,456, granted Jul. 25, 1978, and U.S. Pat. No. 6,157,865, granted Dec. 5, 2000. Coatings for the base material are described in U.S. Pat. No. 3,889,270 granted Jun. 10, 1975, U.S. Pat. No. 4,503,111 granted Mar. 5, 1985, U.S. Pat. No. 4,555,437 granted Nov. 26, 1985, U.S. Pat. No. 5,190,805 granted Mar. 2, 1993 and U.S. Pat. No. 5,206,071, granted Apr. 27, 1993. The disclosures of all of the aforementioned United States patents are incorporated by reference.
As supplied, the plastic sheet material is usually flat, and accordingly, to form a wristband, bracelet, finger ring, or the like, from a decorated strip of such material, it would be necessary to provide for a connection of one end of the strip to the other end. Heating the strip will cause it to curl, but, because shrinkage takes place unevenly, the result is usually not aesthetically acceptable.
There has been a need for a simple, convenient, and reliable way to utilize SHRINKY DINK sheet material to produce wearable jewelry in the nature of finger rings.